Remote control apparatus



June 1942. B. o. BROWNE 2,288,435

REMOTE CONTROL APPARATUS Filed Sept. 24, 1940 FIG. 4/ '42 70.1 I?

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T i Q ATTORNEY Patented June 30, 1942 REMOTE CONTROL APPARATUS Bennie 0. Browne, Maplewood, N. J., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application September 24, 1940, Serial No. 358,126

6 Claims.

This invention relates to remote control mechanism and particularly to tuning mechanism for radio receivers.

An object of this invention is to provide a simple, compact and etficient device for accurately adjusting a tuning shaft of a radio receiver to any of a large number of preselected positions.

Various mechanisms for controlling the tuning position of the condenser or variable inductance elements of radio apparatus are known in the art. One general type of such mechanism is that employing cams for determining the position of the shaft of the tuning element. In such tuners the cams are arranged to operate circuit contacts to interrupt the action of the operating mechanism when the shaft has reached a desired position. Such cams must be readily adjustable so that the position at which the tuner is set to stop can be accurately and easily set and reset. Also, once the cams are set to the desired position, they must maintain their adjustments throughout a continued use of the mechanism. Further requirements particularly in the case of tuning mechanisms for use with radio sets in airplanes or similar service is that the weight and space requirements of the apparatus be kept at a minimum.

These and other objects are achieved by the control mechanism of the present invention, one embodiment of which is shown in the accompanying drawing in which:

Fig. 1 shows a plan view of the tuning control mechanism;

Fig. 2 is a sectional elevation taken along the line 2--2 of Fi 1;

Fig. 3 is a sectional view of part of the cam cylinder 3| and one of the cams 33;

Fig. 4 is a partial detail view taken along the lines 4-4 of Fig. 2;

Fig. 5 is a schematic circuit diagram of the operating circuit of the tuner; and

Fig. 6 is a partial detail view of a modification of the structure of one of the cams.

Referring to the drawing, the main apparatus is mounted in a frame comprising the end members H and I2 joined together by suitable crosspieces 85, 86, etc. J ournaled in the end members H and I2 are two shafts I3 and I4. The shaft 13 carries on its right-hand end the movable plates of a variable air condenser l5 which is controlled by the mechanism. Shaft l4 has on its right-hand end a knob 16 for permitting manual adjustment of tuning condenser l5.

Shaft l4 also carries a worm H which meshes,

with a worm gear I8 carried by a counter-shaft It. On the other end of the counter-shaft I9 is a worm 20 meshing with a worm gear 2l carried by the shaft l3. Through this double worm and gear drive, the motion imparted to the drive shaft [4 is transmitted to the tuning shaft l3 with considerable speed reduction. 5

For remote control, the drive shaft I4 is driven by a motor 22 carrying on its shaft a worm 23 which meshes with a gear 24 which is coupled to the shaft l4 by a clutch 25 which is operated. by the solenoid 26. When the solenoid 26 is deenergized, its armature 21 is in the left-hand position as shown and the clutch 25 is released. When electrical current is applied to the solenoid 26, the armature is moved to the right-hand position causing the clutch 25 to engage the worm gear 24 sothat the motor 22 drives the shaft l4. This movement of the armature 21 to the right by the energization of the solenoid 26 also closes the relay contacts 28.

Within the frame the shaft l4 carries a cam cylinder 3i provided with a plurality of tapered circumferential grooves 32 in which are mounted the cams 33. The shaft [3 carries a similar cam cylinder 4! provided with similar grooves 42 for carrying similar earns 43.

Figs. 2 and 3 show in detail the construction of the cams 33 and the method of mounting them on the cylinder 3!. The construction of the cams 43 and the method of mounting in the cylinder 4| are identical. The cam 33 is in the form of an open-ended circular loop of resilient wire, such as the spring tempered phosphor-bronze. At a point on the circumference of the loop directly opposite the center of the open portion, the wire is bent into a small tightly closed loop and clamped by a ring 34 to form the camming surface 35. The cams 33 are preferably formed in an open-ended circular loop having a diameter slightly smaller than the outside diameter of the cylinder 3| so that they will be fit tightly into the corresponding groove 32 and be clamped therein by the spring action of the wire. This clamping action is-further increased by means of the spiral tension spring 36 which is attached to the two open ends of the loop.

Mounted along the one end of the frame is a metallic bar 45 which is supported by the insulator 5|. Spaced along the metallic bar 45 is a series of contact springs 50. (These like the other contact springs and arms of the device are designated by the decimal designations 501,

50.2 58.5, etc., in order to identify the different groups of similar contacts.) Associated with each contact spring 59 is a contact arm 60 having one end mounted on an insulator ii. The free end carries a roller 62 which is operated by the cam surface 35 of the corresponding cam 33.

Similar arms TH] and associated contact springs 23 are carried along the other edge of the frame and associated with the cams t3.

Along the center of the frame and insulated therefrom by the insulator 73 is a conductor plate M carrying on each end a series of spaced contact points 8! and SI. (The contact points 9! are not shown in the mechanical assembly, being under the corresponding contact arms 98.) Associated with each of the contacts 3! is a contact arm 80 carrying on its free ends a roller 82. Similar contact arms 90 are associated with each of the contacts 9!. Each of the corresponding arms 80.! and 9M 83.5 and 93.5, etc., are formed of a single strip mounted on an insulator Gl'.

In order to permit adjustment of the positions of the cams 33 on the cylinder 3!, there is provided a longitudinal bar 95 mounted on the back of the frame. This bar is provided with two rows of holes 96 and 9'! shown in Fig. 4. The row 96 is arranged for proper adjusting of those cams associated with the contact arms til and the row Ell is arranged for those cams associated with the contact arms 30. A tool 93 having a square shank for fitting into the holes 35 or 9? and a shoulder member 39 is provided for ma ing the adjustment.

When the tool 98 is inserted in one of the holes 95 as shown in the drawing, its inner end will engage one of the ends of the earns 33 and will hold the cams against movement as the cylinder 3! is rotated by means of the knob 39. The position of the bar 95 and the row of holes varying is so adjusted that the tool 98 holds the cam 33 in such a position that the cam surface 35 is in contact with the roller 62 to break the contact between the arm 60 and the contact springs 50.

A similar bar (not shown) With similar rows of holes is provided for the cam members 33.

The resilient action of the wire forming the cam 33 together with the tension of the spring 36 tends to force the cam into the tapered groove 32 thus maintaining it very rigid against rotation by pressure applied to the cam surface 35. On the other hand, pressure applied to one end of the loop by the tool 93 tends to lift the cam out of the groove 32 so that it may be readily rotated to adjust its angular position.

The use of the two sets of cams 33 and 43 provides what may be termed a micrometer control of the angular position of the shaft is and the movable plates of condenser carried thereby. The cams 43 give an approximate adjustment of the position. This is only approximate because each of the cams 33 will operate its associated arm 38 to hold the contacts open through a finite angle of movement of the shaft i3. However, the shaft I4 is driven at a higher speed than the shaft l3. As a result the angle of movement of the shaft M in which any one of the cams 33 will operate its arm fill will correspond to a very small angle of movement of the shaft l3. contacts operated by a cam 33 in parallel with one of the sets of contacts operated by a cam 53 the motor 22 can be caused to stop only when the two cams are in position to open their corresponding contacts. This will provide a very By connecting one of the sets of l accurate adjustment of the angular position as will be more clear from the following description of the operating circuit as shown in Fig. 5.

The complete circuit includes, in addition to the schematic showing of the apparatus already described, a battery 88 which supplies the energy for the operation of the device and a control switch 89. In the position in which the switch 39 is shown, the device will just have been operated to bring it to the position shown in all of the figures of the drawing in which the respective one of the cams 33 and 43 will be in the position to operate the arms 63.5 and 18.5 to open the corresponding contacts. With both of these contacts opened, the circuit from the battery E3 through the solenoid 2G is opened thus releasing the clutch 25 and opening the contacts 28 through which current is supplied from the battery 83 to motor 22.

Now if the switch 30 is moved to the contact 87, a circuit will be established from ground through switch 89, contact arms 3 0.5 and 3&5 and their associated contacts 3G5 and H5 in parallel, solenoid 25, battery 83 to ground. This will operate the solenoid 26 to engage the clutch 25 and at the same time to close the contacts 23 establishing a circuit for the motor 22 from the battery 83. The shaft ill will then be driven by the motor 23 at the same time driving the shaft [3 and the associated condenser l5 through the counter-shaft it. When the shaft 53 has reached the point where the corresponding cam 43 operates the arm 93.5 to open the circuit at contact 9L5, the circuit will still be established through the contact 8L5. Ihe motion of the mechanism will continue until the corresponding cam 33 is in such a position as to operate the arm 30.5 to open the circuit at contact 8L5. This completely breaks the circuit from the grounded end of the battery 83 to the solenoid 26 and releases the clutch 25 at the same time breaking the electrical circuit to the motor 22 at contacts 28. Due to the large reduction gearing between the shafts ill and IS, the cam surface 35 of the cam 33 will maintain the arm 33.5 in the operated position until the cam 33 has reached such a position as to operate the arm 80.5 to open the parallel circuit,

In setting the tuner for any particular position, for example, that determined by the contact arms 59.5 and 76.5, the tool 9-3 is inserted in that one of the holes corresponding to the cam 33 which operates the contact arm as shown in Fig. 2, At the same time the other tool is inserted in the hole of the other bar (not shown) corresponding to the cam 413 which operates the contact arm lot i'hen as the knob I6 is turned to adjust the condenser if: to the desired position both of the particular earns 33 and 613 Will be held by the corresponding tools in such positions as to maintain the contact arms 60.5 and 13.5 operated to open their contacts. When the knob it has been adjusted so that the condenser 55 is in the desired position the tools are removed. The cams then will be adjusted to the proper angular positions on the respective cylinders 3i and All to cause the mechanism to return to the same position when the proper contact of switch 89 is closed.

What is claimed is:

1. In a device of the character described, a cylindrical member having a tapered wall circumferential groove and a cam member adapted to be adjustably mounted in said groove, said cam member comprising a split ring of resilient material.

2. In a device of the character described, a cylindrical member having a tapered wall circumferential groove and a cam member adapted to be adjustably mounted therein, said cam member comprising a split ring of resilient material, the diameter of said ring in the unstressed condition of said material being smaller than the diameter of said cylinder.

3. In a device of the character described, a cylindrical member having a tapered Wall circumferential groove and a cam member adapted to be adjustably mounted therein, said cam member comprising a split ring of resilient material, the diameter of said ring being smaller than the diameter of said cylinder when said material is in an unstressed condition, and a tension spring attached to the ends of said split ring.

4. In a device of the character described, a cylindrical member having a tapered wall circumferential groove, and a cam member adapted to be adjustably mounted in said groove, said cam member comprising a split ring of resilient material having a raised portion at one point on the circumference of said ring adapted to operate a contact member.

5. In a device of the character described, a cylindrical member having a tapered wall circumferential groove, and a cam member adapted to be adjustably mounted in said groove, said cam member comprising a split ring of resilient wire, one portion of the circumference of said ring being bent to form a raised cam surface and the diameter of said ring in the unstressed condition of said material being smaller than the diameter or said cylinder.

6. In a device of the character described, a cylindrical member having a tapered wall circumferential groove, a cam member adapted to be adjustably mounted in said groove, said cam member comprising a split ring of resilient wire, said wire being bent at one portion on the circumference of said ring to form a raised cam portion and the diameter of said ring in the unstressed condition of said material being smaller than the diameter of said cylinder, and an adjusting member arranged to engage one end of said split ring when said raised cam portion is in the operating position to permit the adjustment of said cam by the rotation of said cylindrical member.

BENNIE O. BROWNE. 

